1. Field of the Invention
The present invention relates to an intruding metal detection method for an induction type power supply system, and more particularly, to a method of determining the existence of an intruding metal before power delivery of an induction type power supply system starts.
2. Description of the Prior Art
In an induction type power supply system, a power supply device applies a driver circuit to drive a supplying-end coil to generate resonance, in order to send electromagnetic waves. A coil of the power receiving device may receive the electromagnetic waves and perform power conversion to generate DC power to be supplied for the device in the power receiving end. If the electromagnetic energy sent by the supplying-end coil is exerted on a metal, it may heat the metal. The accumulated heat energies may cause high temperature on the metal, which may burn surrounding objects and thus generate damages. In the prior art, in an induction type power supply system, driving operation in the power delivery process may be periodically interrupted to detect the intruding metal. If an intruding metal is found, the system may stop sending electric power. After a period of time, the system may restart to send electric power. Subsequently, the electric power is sent for a period of time, and if an intruding metal is detected, the system may stop sending electric power again. In such a manner, the iteration may still heat the metal object, and it is dangerous after the heating operations last for a long period.
Thus, there is a need to provide another intruding metal detection method which is capable of performing determination before the induction type power supply system starts to send power, and thus power delivery operation may not be activated when an intruding metal is found, in order to realize a more effective mechanism of intruding metal protection.